【数据存储】备份分级：全量加增量的组合策略

---周日全量，其余每日增量
setontimerex(68, 600)
function Backup.tick()
    local hm = tonumber(os.date("%H%M"))
    if hm ~= "0300" then return end
    local wday = tonumber(os.date("%w"))
    if wday == "0" then
        Backup.full()
    else
        Backup.incr()
    end
end

function Backup.full()
    DB.backupAll("full_" .. os.date("%Y%m%d") .. ".bak")
    Backup.verify("full_" .. os.date("%Y%m%d") .. ".bak")
    Backup.prune(35)     -- 全量留 5 个
end

function Backup.incr()
    DB.backupSince(Backup.lastFullAt(), "inc_" .. os.date("%Y%m%d") .. ".bak")
    Backup.prune(14)     -- 增量留 2 周
end

---季度演练：备份恢复到临时实例
setontimerex(69, 0)
function Backup.drill()
    local latest = Backup.latestFull()
    local t0 = os.time()
    Backup.restoreTo(latest, "drill_instance")
    local ok = Drill.smokeCheck("drill_instance")
    Ops.log(("drill %s rto=%ds"):format(
        tostring(ok), os.time() - t0))
end